1. Field of the Invention
The present invention relates to a structure for heat dissipation of an integrated circuit chip and a display module including the same. In particular, the present invention relates to a heat dissipating structure for an integrated circuit (IC) chip capable of effectively dissipating heat created by the chip to the outside, and a display module including the same.
2. Description of the Related Art
Plasma display modules are flat panel displays that use a discharge gas to display images. The technology enables the manufacture of low-profile screens, and allows for the formation of large-scale, high resolution displays with a wide viewing angle. Thus, interest in plasma display modules has grown.
Plasma display modules typically include two flat panels, or substrates, disposed to face each other and having discharge cells disposed between the two panels. After a discharge gas is injected into the cell, the cell is sealed, thereby forming the plasma display panel. A voltage is applied to electrodes traversing the discharge cell, inducing an emission of light from the gas in the discharging cell. In particular, the discharge gas produces ultraviolet rays, which excite phosphors to produce visible light, thus forming an image.
The voltage applied to the electrodes is controlled in response to a video signal received from a video source. The plasma display module may include one of more IC chips on a circuit board for driving the plasma display module. The IC chip may simultaneously control a large quantity of video signals, and may be subject to a heavy load, and therefore may generate a considerable amount of heat. An intelligent power module (IPM) can be used as the IC chip for a plasma display module. An IPM may generate more heat than in an ordinary IC chip, due to the design of the IPM's integrated circuit.
Referring to FIGS. 1 and 2, plasma display modules may include one or more heat sinks 60 to dissipate heat from IC chips. The heat sink 60 may be attached to the rear of an IPM or other driving circuit chip 55 disposed on a circuit board 51 using, e.g., an adhesive 63. The heat sink 60 may include a base portion 61 and a plurality of heat-dissipating fins 65 extending from the base portion 61. The fins 65 may define a plurality of air passages RA between them.
Typically, as illustrated in FIGS. 1 and 2, a heat sink 60 in a plasma display module is oriented such that the fins 65 and the air passages RA between the fins 65 run in an upper to lower direction. That is, where the plasma display module is oriented in it's ordinary viewing position, with it's major viewing surface oriented perpendicular to the floor so as to be facing the viewer, the fins 65 of the heat sink 60 are oriented vertically, projecting horizontally from the base portion 61 with long edges of the fins 65 extending vertically, in an up-down orientation, such that the air passages RA extend upward between the fins 65. Accordingly, hot air 11 created by the IC chip rises in the air passages RA through convection, i.e., it flows in the air passages RA between the fins 65 from the lower part to the upper part in FIG. 1, thereby dissipating heat from the IC chip 55.
For a high-power IC chip 55, it may be necessary to provide a large heat sink 60. However, if the heat-dissipating fins 65 are extended in order to adequately cool the IC chip 55, the air passages RA are extended accordingly. In this case, the hot air 11 that received heat radiating from the lower portion of the IC chip 55 rises upward along the air passages RA that extend from the bottom to the top, getting hotter as it rises upward. As a result, the heat transfer from the top portion of the IC chip 55 may be diminished, and thus heat may not be dissipated effectively.
In addition, because a plasma display panel may have multiple IC chips 55 disposed in close proximity to one another, in the case where multiple chips arranged one above the other in a column, as illustrated in FIG. 1, the hot air 11 radiated from a lower IC chip 55 rises up through the heat sink 60 of the lower IC chip 55 to a heat sink 60 of an upper IC chip 55 directly above. Therefore, the upper IC chip 55 is cooled with the hot air 11 instead of cool air, such that it is less effective at dissipating its own heat.